Last night I took a number of guided shots of comet Neowise with a 500mm telephoto lens. Each image used for stacking was a 30 second exposure with the ISO set to 800. Since the comet was moving relative to the background stars, I first made an image of just the comet by subtracting out the stars and aligning and stacking the comet only. I then took the same images and subtracted out the comet and aligned and stacked only the stars. The first image below shows the result of combining the two stacked images to produce an picture that doesn't show trailing in either the comet or the stars. The next image shows the first frame taken at 10:14PM, the last image shows the frame taken at 10:59 PM. If you download these images you can see how much the comet moved relative to the background stars in just 45 minutes. The last image was actually 45 seconds long but appears redder and dimmer than the image taken at 10:14PM due to being so much closer to the horizon so we are looking through much more of the earths atmosphere. All questions, comments and suggestions are welcome.

Yeah, my interest peaked with that.


Amazing images, Ballard!
I'm just fiddling. I have to head to Washington next week for a Grandson's wedding. They've asked me to officiate since I'm ordained but inactive. They want a short and sweet on the lawn in front of their Victorian home.
And I've taken my equipment up there, but they call Washington the Evergreen State for a reason. At least where the family lives anyway. I call it No Sky.
So just getting a few days at the NEOWISE.
I think watching it with our 10 x 50's is pretty good, too.

Glad you got such fantastic shots.